The present invention generally relates to a disk drive apparatus, and, more particularly, to an improvement of an initialization process by which the disk drive apparatus is set to a read/write enable state. More specifically, the present invention relates to a disk drive apparatus having a replaceable disk.
Various types of disk drive apparatuses are known. An optical disk drive apparatus or a magneto-optical disk drive apparatus has an extremely large storage capacity and is thus expected to be used as a large-capacity storage unit of a computer system. There is known an optical or magneto-optical disk drive apparatus which has a replaceable optical disk. An optical or magneto-optical disk is inserted into the disk drive apparatus through a disk loading mechanism where a spindle motor is in a stationary state. When the loading of the disk is completed, a loading complete detection signal is generated and output to the spindle motor. The rotating speed of the spindle motor starts to increase toward a constant speed equal to, for example, 3600 rpm. After the spindle motor reaches the constant speed, an initialization (adjustment) process is carried out.
As shown in FIG. 1, an initialization process including a first focusing adjustment, a phase encoded past read adjustment, a laser diode (LD) light emission adjustment and a second focusing adjustment is carried out after the rotating speed of the spindle motor reaches the constant speed. During both the first and second focusing adjustments, an object lens is moved within a predetermined range and a focus servo control is pulled in. During the focusing adjustment, a laser diode is adjusted so that a predetermined read power and write power are obtained. The PEP read adjustment determines whether or not PEP data recorded in a PEP zone as defined by the ISO/IEC DIS 10089 are correctly read out. After completing the above-mentioned adjustment processes, the disc drive apparatus is set to a read/write enable state (ready-ON state) where data is read out from or written on the disk.
However, conventional disk drive apparatuses as described above have the following disadvantage. As described above, the initialization process is carried out after the spindle motor starts to rotate at the constant speed, and the disk drive apparatus is set to the read/write state after the initialization process is completed. Thus, it takes a long time to obtain the read/write enable state. In the case where the rotating speed of the spindle motor is increased up to 1800 rpm, it takes about five seconds to obtain the read/write enable state.